Negative keywords can help advertisers refine the targeting of their ads by:

Negative keywords can help advertisers refine the targeting of their ads by:

  • Raising the average position of their ads.
  • Reduce the number of irrelevant clicks
  • Increasing the number of relevant Display network placements
  • Reducing their campaigns daily budget recommendation.

Answer : Reduce the number of irrelevant clicks

Source: https://support.google.com/adwords/answer/2453972?hl=en&from=63235&rd=1